Dynamo-cooling system



Nov. 13, 1928. v

F. G. BAUM Dumm cooLING SYSTEM Filed nec. 6. 1927 zsheets-*sneet 1 INVENTOR.

A TTORNEY n F. G. BAUM DYNAMO COOLING SYSTEI Filed Dc. 6, 1927 l2 sheets-sheet 2 ,f l Y Mob-QM operation ofthe machine,

PatentedNov. v13,

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My invention relates :to-"d machines comprising rotor an a method of cooling the same.

Inthe use of apparatus of the class men;

tioned there is always a develo ment of healt, t e.-

fto absorb the heat and thereafter allowed to especially in the windings an vcores of stator and rotor, and as these heat units are being. produced continuously during the the rate at which such heat units can be disposed'of determines its capacity, or in othr words by providing means for increasingl the rate at which lrotor and stator vpart wit y from a smaller apparatus. This means a' su tantial and limportant increase in continuous ratin o^f a dynamo-electric machine, and accor ingly a greatly improved e lower cost of production, from which follows a reduction in the cost of operation in the handlin of electricien'ergy. i

Various evicesand met ods have beeii` a cooling liquid', for instance, brine, through expensive to'operateyand any' time likely to reason of leakage of the cooling li 11uid .from the pipes/through which it is circu ated.. In some 'cases it has been suggested to Aapply 35` a stream or sprayof'water to the apparatus.-

' nary d namosince the use of water would destroy the insulation '.within avery short time,v a

Accordingly, for a.. 'venai'iiount of cooling ing; loss Iof energy through. the churnii'igof the oilby 4therotating parte.v In order to avoid.-

' of ionmagnetic material.' *Y

` however. prevents a 'circulation-. effvolfrom*r rotor to stator and `through the a`p'ar'atua,-fl A Pand detracts irom the. 'e ect,I and;

This however cannotbe done with an i ordi- It has also been pro `rotor and stator in o i "contained ifn ahousin which casethere 'willbe a prohibitive lratetlfe rotor fromthestatpruca partition v s. 'y i ,partition furthermore does'not do awaywithlosses due to churning or frct'ionbetween rotor and nemo-,electric stator and to.

their heat units, I Yain able to develop greateruseful energy fromv the same apparatus, or equalener performance and a 1 gipes enclosed within the `rotor sed to submerge the- In prior application Serial No. 02 filed ay 18, 1927, I have disclosed ,ind broadly claimed a dynamo electric machine `iii which yoil or othersuitable fluid having a high thermo-Stora e capacity is applied inl finely divided con ition to' rotor and stator collect in a suitable receptacle, for' use in a continuous manner. The present application` the circulation of the cooling liquid.

. Reference is hereby made to thejaccomf panyiiig d rawing of which Fig.v 1 is a. trans verse vertical section of a generator or dynamo constructed in accordancewith my invention, the section being taken upon line 1--1 orzFig. 2'. Fig. is a section on line 2442 of Eig. 1. Fig. 3 is a transverse vertical section `of 'a dynamo/"or motor of another type embodying my "invention, thev section linebe' ing indicated as the line 3-7-3 o'fFi 4, and- Fig. 4 is a central vertical section o the de- 'vice .of Fi 3.

It is wel known that oil,A has a very'mu'ch higher specific heat than air, and that accordingly the cooling eiect which can be obtained from it is much greater. For' instance, Oil has a weight of about 55 pounds per cubic-foot,

while air-has a weight of about .0.08 ounds percubic foot. The s ecific heat ofoilisbout 0.5, where that of air is about 0.237. The ratio of vheat absorbing capacity of veqiialvolumes of air and of oilisthen given by the -followiiigequation:

orabout145() times.

' much ess volume of oil need'be used than o air alone, and if a mixture ofoil ingeect is very much less than the volume `of-air alone, depending -upon vthe ratio of oil to air in 'lthe mixture used;l The oil Iis preferablyapplied;in the form of a spray,

or mist, or in relatively. small drops, so/that a yminimum ofvchurning'eect is' produced in theniixture by the movement of the rotor,` and so. thatfn'o sin le 'particle is 'siiicien'tly large -toproduce'un ulyl large impactvforees when. l

it is thrown from the moving rotor to the stator. n

To prevent loss of oil, the circulating medium should be enclosed; The" dynamo-elec-- tric machine may be provided with closed end plates and frame with a reservoir at the bottom, so that as the oil sprav strikes the stator it may drain down over the hot surfaces of the machine to the reservoir, after which it may be recirculated. The mixture of liquid and gas may consistof a fluid, such as oil, and air, or it may preferably consist of a less flammablemixture. For this purpose, it may consist of a mixture of oil spray and carbon dioxide, with or without the inclusion of a small proportion of air,;or it may consist of a mixture of oil and nitrogen, also with or 'without the inclusion of small quantities of air, insufficient to produce a combustible mixture with the oil.

One embodiment of the device of my invention is shown in Figs. 1 and 2. These ligures show the' essential parts of a typical dynamo-electric machine to which the improvement of m invention may be advantageously applied. he machine may consist of a shaft, 1, supported in bearings, to which is attached a rotor 2. The rotor may be a rotating field or a rotating armature, as desired. In the embodiment shown, it is indicatedas a ro-' l separators (not shown) being placed between the various groups to form interspaccs or passages 8 for the cooling medium and which extend entirely through the core in a radial or outward direction. Windings 7 are positioned in appropriate slots in thek stator core. A suitable frame member 9 is provided for the support of the laminations forming the stator, and both statorand rotor are entirely enclosed by a housing formed of members 11 and 12 which fitclosely about the bearings of shaft 1 and frame 9. The rotor also hasy fan blades 13 as shown for causing a circulation of the `air or other gas contained in the housing 11, 12,fof the machine.

The base ofthe housing 11, 12 is formed with a reservoir 16 which will contain a sutlicient quantity of oil for carrying out thecoolinn' method, and all -ot theoil which is applied to the heated parts for cooling purposes will by action of gravity find its way down into this reservoir through the various openings which are. shown. Means are rovided for a continuous circulation of oil om this reservoir which will now be described:

Upon each end ofthe rotor shaft l are mounted a .plurality of arms, blades or vanes 18, the'lower ends of which enter the reservoir 16 and remove liquid therefrom continuously during the operation of the device. The wall of the housing is formed with two tangential pockets, 19 and 20 respectively, which open directly into the spacewithin the housing and in such position that the pocket 20 will receive oil from the vanes 18 in case the direction of rotation is clockwise Fig. 1, and the pocket 1 9 will receive the oil discharged by the vanes in case the direction of rotation is counter-clockwise. There is a pipe 14 which leads downwardly from the bottom of the pocket 19 to a point within the outer circumference of the rotor. This pipe occu. pies a space between one set of vanes 18 ,and

the rotor andthe lower end of the pipe is bent the rotor. There is a similar pipe 23 extending from the pocket .20, which pipe is positioned between the other-set of' vanes 18 and the rotor and its end is 'also bent inward so that the oil passingthrouh the pipe will fall into one ofthe pans 22. 'he pans 22 are provided with perforations or openings 24 extending therethrough, and of such size as to provide a plurality of fine sprays of oil in the air gap between the rotor and stator. The size of' these perforations may vary considerably'as well as their number and they will ordinarily be so designed that theK cooling oil which is received in the pan will not be entirely exhausted therefrom until the pan has substantially completed itsrotation to bring it into position to receive a fresh supply of oil from the pipe 1.4 or 23.

Provision may be made for the Vpassage through the rotor of currents of gas created by fan blades 13 and other movin parts of the rotor. Passages may be forme through the body of the salient poles 3 oi' preferably between the poles. Eitherconstruction pro- 'I vides currents of air or gas which mingle with the oil sprayed from the pans 22. The perforations 24 of thepans 22 ma. `desirably be so placed as to provide a p urality of sprays of oil in.radial alignment with the Ventilating passages 8 in the stator.4 l

The current of fluid from the pans 22 of the rotor is directed towards the inner surface of the stator in the bore thereof, and towards the inner openings of the Ventilating passages therethrough. The greatly increased thermal capacity of this fluid, as compared toair. alone, is thus available for the cooling both of the rotor member and the stator member. A portion of the oil may pass through the Ventilating passage 8 in v'located in the plane of the Ventilating pasto forthe desired cooling eiect, and it is enfas.

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collect a substantial amount of heat there-fv from, either by radiation or by convection. It is .desirable that the spray pans 22 be so positioned that the openings 24 through which' theoil is discharged and sprayed e sages 8, in order to discharge as' large a portion of the oil through thev ventilatin passages as possible, and to minimize t e accumulation of oil within the -air gap between the rotor and stator. While some of theoil spray is carried freely through thev passagesl 8, other portions ma strike the surfaces thereof,-and coalesce t ereon into a layer o f liquid. This layer may-be carried radially outward along the surfaces of the ventilating passagesaby the current of mixed air and oil spray'. In 1ts\passage over these surfaces, the oil layer is advantageously related thereabled to absorb a substantial amount of heat .in the course of the flow. The oil is thus car-v ried to .the outer surface of the stator,l through downward to. the reservoir 16 at the bottom of the housing. f

In order to remove the heat from thel oil in the reservoir 161 provide a. cooling coil throu h which there is a continuous circu lation o water by way of inlet 36, and outsuitable circulatory means b eingf.;l

` 4tilatmg ducts are employed' it is ossible to let 37, any

' provided. f

' The structure shown in Fig. 3 has been designed moreparticularly for units of small size, asfor-` example motors used for a great variety 'of purposes, sometimes inv position where they `are ex d' tounfavorable weather conditions, ampness, ctc. `The structure shown resembles in a genis a rotor 2 and two setsj of radial arms,

blades or vanes 18 mountedon shaft l and l 'Y -there is also a stator 5', and stator frame 9',

.. ing formed all .of which parts are 'enclosed Within a"hous y members 11 land 12. The

A structure-.ofthe stator fand vframe 9 is the 1 and 2. vThe interior of the rotor is formed vwith a'trough`30 for-'receiving oil from the v pockets 19 'and 20 through the pipes 14 'and 23'.. The rotor'shown is. of the ,well knownf same as that of' staton 5 and frame' 9, Figs.

squirrel cage type and -consists of laminations 25 having peripheral slots inwhicharev positioned the indutor barsv 26 characteristic of this typel of machine.- The oil may be. conductedthrou lfsuitable channelsl 2 7 Jin,v the rotor rom the trough\30 to the' rotor. surface, at which point it may be sprayed` by any lappropriate means, which may consist ofjet plugs or'other spray der' Vvvices positioned within and` nea-r t ends of the channels 27. The rotor has fanv e outer blades l13 which act -similarly ,to blades 13 ofFi'g; 1 There isa reservoir v16 in the base [thermal capacity of afgiven volume of t "cooling iu1dit is .,thuspossible; to obtain of thehtusin iig-12', ofsumcienesize to 'receive the oi used in themachine, suitable openings being provlded to enable the oil to descend thereto from allpoints.

The ends of the aussages 27 are desirably positioned in the p ane of the Ventilating passages 8 asA revio'usly described, and the oil spray toget er with a' ortion of gas as vlously described is discharged into em for the production of a similarl coolin leffect upon'the structures. -Thecooling oi flows over the warm surfaces collecting heat and -ing means and subdivide theoil to such extent as to create a fog of oil within the hous- Jing.; By this construction very eicient cooling means are provided and. much highery load capacity is obtainableirom a'given-eon'- struction... f

Byithe device of my "invention it isipossirep ble to obtain very much more-effective cooling of dynamo machinery, beca se of the much hi herthermal capacitylo the fluid employ for cooling. Because ofthe high equally eiective cooling to` that obtanedby air, by '.theuse of very muhlgsma'ller ventilati'ngducts, or if the maximum size of venevice-of my`construction thus makes it possible to increase the duty on dynamo-electric machinery, thereby. much reducing the cost ofmachinery for aggiven power outlput, since .the additional parts required for the applica:-

tion 'of the devicev of my invention` are. very small-.itemsin the cost ofthe machinery. Thus a directreductionof the cost of electric power is provided.

Further advantages o vention are found in the fact that the' cooling system may be -made completely closed. re' .clrculatinga veniiuid as 1t is needed. Thus lno external Aair need be supplied, and the conveyors and ducts which wouldfor such supply, are saved. Likewise the elimina-tion of the need for l-cooling'air reduces the amount of dirt and moisture-which would otherwise be carried into the machine by such circulating air. In consequence, the

insulationfcon'dition of the machineis much y improved, and the necessityfor frequent cleaning 'to remove dirt and other obnoxious f the device of .myin-V- 'l material is avoided.- The presence of the oil directly adds to the insulation '-resistance, be-

cause of itsown yhigh insulation value and because of theelimination offmoisture. Like- 'wise the the machlne in a none-combustible atmosphere, thereb greatly reducing the severity ofany kfires w ich may occur in the insulation stem makes it possible to enclose due to overload, excess voltage, and other factors which tend to injure` Likewise in the event that fire occurs in the insulation, 'it 'is smothered at once 'upon the removal of load from the machine, by the cooling eiect of the large quantities of oil thrown in, and by the lack of oxygen to support combustio The device of my invention is particularly applicable to relatively large dynamo mac ines, such as generators, rotary converters, andlarge motors. Itis, however, equally well adapted to application to the smaller types of industrial motors, and is also appli cable to railway and other transportation motors. In such service it is particularly advantageous because when so equipped, the

motors are-operating in a medium having a very high insulat1on resistance, as compared to operation under ordinary conditions where thev are in a medium charged with moisture and `other matter, tending towards a low insulation resistance. s

Having nowdescribed I claim is: I

1. -A dynamo-electric machine omprising a rotor, a stator, a housing enclosing the my invention', .vliat same, a reservoir within the housing, an arm secured to the rotor and yextending into the reservoir, a stationary pocket .having an bpening in position to receive liquid thrown by said arm, and a 'conduit for permitting the ow of liquid from said pocket to the interior of the rotor. A.

2. A dynamoelectric machine comprising l a' rotor, a stator,"a,housing enclosing the same and having anfinterior pocket, a reservoir within the ousing, andmeans for circulating liquid by centrifugal action from the reserl'byqsaid arm.

4. A dynamo-electric machine comprising` enclosing the i a rotor, a stator, a housin same, a reservoir-within the ousing, an arm secured to the rotor and extendin into the reservoir and a stationary pocket avingan opening in position to receive liquid thrown J 5.l A dynamo-electric machine comprising tlie insulation.

a rotor, a stator, a 'housin enclosing the` same, a reservoir within the ousing, an arm secured to the rotor and extending into the reservoir and a stationary pocket integral with said housing and having position to receive liquid thrown by said arm.

6. A dynamo-electric machine comprising a rotor, a stator, a housin enclosing the same, a reservoir within the housing, an arm secured to the rotor` and extending into the reservoir and a stationary pocket arranged tangentially with respect to the path of the extremity of said arm and having an opening in position' to receive liquid thrown by said arm. y

7. A dynamo-electric machine comprising a rotor, a stator, a housing enclosing the same, .a reservoir for cooling liquid, an arm secured to the rotor and extending vinto the Vreservoirfsaid arm being spaced fromthe rot'orha stationary pocket to receive liquid thrown by said arm and a conduit for the Aiiow of liquid from said pocketl to the rotor,

said conduit occupying tlie space between said arm and said rotor.

8. A dynamo-electric machine comprising a rotor, a stator, a housin enclosing the same, a reservoir within the housing, an arm secured to the rotor and extending into the reservoir, a stationary pocket havin an openv ing in position to receive li uid t rown by such arm, a conduit exten lng downward from said pocket and toward the rotor shaft, the lower end of said conduit beingbent inward and extending across the plane of rota-- tion of one end of said rotor.

9. A dynamo-electric machinegcomprising a rotor, a stator, a housing enclosing the same, a reservoir, an ar'm secured to the rotor and extending into the reservoir, and a stationary pocket to receive liquid thrown by said arm when rotating in one direction, and anotherstation'ary pocket to receive liquid thrown Aby said arm when rotating in the opposite ,direct-ion,-a conduit for fiow of'liquid' from `oneof said pockets to the' interior of said g `rotorand a conduit for .flow of liquid from y the other pocket to the interior of the rotor,

said conduits being at opposite ends of the rotor. j

10. A dynamo-electric machine comprising a rotor, a stator, a housing enclosing the same, a reservoir forlcooling liquid, arms secured to the rotor at either end thereof and spaced therefrom, stationary pockets to reqceive liquid thrown by said arms when rotating 1n either'direction, and a condult'for the flow of liquid from each of said pockets to the rotor, said conduits respectively occupying the two spaces between thel ends of the rotor and'said arms. v

11. In a dynamo-electric machine, a rotor member and alstator4 member, a` housing 'enclosing the same, a reservoir for cooling liquid, a stationary pocket, a conduit extending lll() from saidl pocket to the interior of the rotor,

means' operating by--centrifugal force for contmuouslv removing liquid from.the reseran opening in voir and supplying it to said'pocket, and

member and a statormember, a housing enclosing the same, a reservoir for cooling hquid, a statlonary pocket, a conduit extending t'ronrsaid pocket to the interior of the rotor,

means operating by centrifugal force for continuously removing liquid from the reservoir and supplying it to said pocket, and' means for permitting the flow of said liquid through said rotor and stator in an outward direction.

In witness whereof, I hereunto Subscribe my signature.-

FRANK G. BAUM. 

